Spool



FIG. 1 is a first perspective view of the spool;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof. 

The ornamental design for a spool, as shown and described. 